Luminous source apparatus, image projecting apparatus and image projection converting apparatus

ABSTRACT

A luminous source apparatus, an image projecting apparatus, and an image projection converting apparatus to prevent a projected image, or an electronic image obtained through electronization of the projected image from intensity variations. A photosensor detects the light-emission quantity from a light-emission lamp in order to regulate the current supplied with the light-emission lamp according to a light-quantity detecting signal from the photosensor, so as to make the light-emission quantity from the light-emission lamp constant. Projected light-quantity onto a movie film is regulated and an image obtained from a shooting section becomes an image having a good quality with a little flicker.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 10/161,024,filed Jun. 3, 2002, now abandoned which is a continuation of applicationSer. No. 09/266,077, filed Mar. 10, 1999 now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image projecting apparatus,projecting an image by projecting light onto a recording medium in whichthe image is recorded, and a luminous apparatus used for the imageprojecting apparatus, and an image projection converting apparatus,converting the image, projected by projecting light onto the recordingmedium in which the image is recorded, into an electronic image.

2. Description of the Related Art

An image projection converting apparatus called telecinematographyapparatus which converts a movie film in which an image is recorded intoa video image is known. Generally the telecinematography apparatustransports a movie film intermittently and projects an image byprojecting light onto each of frame images, while performingelectronization of the projected image with an image pickup device toconvert it into video signals.

According to such image projection converting apparatus, as a widebandwidth including three colors R(red), G(green), B(blue) and asufficient light-emission quantity are required for a luminous source,emitting light to be projected onto the movie film, a luminous sourcesuch as a xenon lamp, for example, is widely used.

However, in such luminous source, inert gases sealed in a housingproduce convection by heat-producing, causing light-quantity variationcalled flicker. Therefore, the level of light projected onto the moviefilm varies, resulting in frame-by-frame variation of the intensitylevel of the projected and picked-up electronic image, i.e. a problem ofdeterioration of the quality of the obtained image.

The problem does not only relate to an image converting apparatus suchas the telecinematography apparatus, but also to a typical projectorused in a cinema theater, for example, or to a liquid crystal imageprojecting apparatus, configured to project an image formed by aliquid-crystal display device onto a screen.

It is an object of the invention to provide a luminous source apparatus,an image projecting apparatus, and an image projection convertingapparatus for suppressing harmful intensity variation of a projectedimage.

A luminous source apparatus of the invention, being used in an imageprojecting apparatus, which performs image projection by projectinglight onto a recording medium in which an image is recorded, comprises:a luminous body emitting light to be projected onto the recordingmedium; means for detecting the light-quantity emitted from the luminousbody; and means for regulating the light-quantity emitted from theluminous body based on the result of the detection by the means fordetecting the light-quantity, so as to make the light-quantity projectedonto the recording medium constant. A recording medium may beimplemented with a movie film, or a group of liquid-crystal displaydevice, for example.

An image projecting apparatus of the invention, performing imageprojection by projecting light onto a recording medium in which an imageis recorded, comprises: a luminous body emitting light to be projectedonto the recording medium; means for detecting the light-quantityemitted from the luminous body; and means for regulating thelight-quantity emitted from the luminous body based on the result of thedetection by the means for detecting the light-quantity, so as to makethe light-quantity projected onto the recording medium constant.

Another image projecting apparatus of the invention, performing imageprojection by projecting light onto a recording medium in which an imageis recorded, comprises: a luminous body emitting light to be projectedonto the recording medium; means for detecting the light-quantityemitted from the luminous body; means for closing and opening thelight-path from the luminous body to the recording medium; and means forcontrolling the opening/closing operation of the means foropening/closing light-path based on the result of the detection by themeans for detecting the light-quantity, in order to make the accumulatedlight-quantity projected onto the recording medium constant. The meansfor controlling opening/closing light-path may be configured to beginthe accumulation of the light-quantity detected by the means fordetecting the light-quantity at the point of making the means foropening/closing light-path in opened state, and to make the means foropening/closing light-path in closed state at the point of theaccumulated light-quantity reaching to prescribed value. Or the meansfor controlling opening/closing light-path may also be configured toaccumulate the light-quantity detected by the means for detecting thelight-quantity for a given period before making the means foropening/closing light-path be in opened state, while obtaining theopening period of the light-path of the means for opening/closinglight-path based on the accumulated value, and to make the means foropening/closing light-path be in opened state for the obtained openingperiod of the light-path. The means for opening/closing light-path maybe implemented with a liquid-crystal shutter.

An image projection converting apparatus of the invention, performingimage projection by projecting light onto a recording medium in which animage is recorded and converting the projected image into an electronicimage, comprises: a luminous body emitting light to be projected ontothe recording medium; means for detecting the light-quantity emittedfrom the luminous body; means for picking-up image projected byprojectinglight from the luminous body; and means for regulatingintensity level of the image signal obtained through the means forpicking-up image, based on the result of the detection of the means fordetecting the light-quantity.

According to the luminous source apparatus or the image projectingapparatus of the invention, the light-emission quantity of a luminousbody is detected by the means for detecting the light-quantity, and thelight-emission quantity of the luminous body is regulated based on theresult of the detection. Hereby, the light-quantity projected onto arecording medium is regulated to be constant, resulting in reducing theharmful intensity variation of an image projected by light.

According to another image projecting apparatus of the invention, thelight-emission quantity of a luminous body is detected by the means fordetecting the light-quantity, and the light-path from the luminous bodyto the recording medium is closed and opened, based on the result of thedetection. Hereby, the accumulated projected light-quantity is regulatedto be constant, resulting in avoiding the intensity variation of theprojected image caused by the light-quantity variation of the luminousbody.

According to the image projection converting apparatus of the invention,the light-emission quantity of a luminous body is detected by the meansfor detecting the light-quantity, and the intensity level of the imagesignal obtained by the means for picking-up image, which picks up theimage projected by projecting-light of the luminous body, is regulated,based on the result of the detection. Hereby, the intensity variation ofthe picked-up image signal caused by the light-quantity variation of theluminous body will be avoided.

Other and further objects, features and advantages of the invention willappear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration showing a diagrammatic configuration of animage projection converting apparatus as an image projecting apparatusincluding the luminous source apparatus related to the first embodimentof the invention.

FIG. 2 is a block diagram showing the configuration of thelight-quantity regulator shown in FIG. 1.

FIG. 3 is an illustration showing the variation condition of thelight-quantity detecting signal outputted from the photosensor of theluminous source apparatus.

FIG. 4 is an illustration showing a diagrammatic configuration of animage projection converting apparatus as an image projecting apparatusrelated to the second embodiment of the invention.

FIG. 5 is an illustration showing the operation timing of the imageprojection converting apparatus shown in FIG.4.

FIG. 6 is a flow chart showing the operation of the shutter controllershown in FIG. 4.

FIG. 7 is an illustration showing the operation timing of an imageprojection converting apparatus as an image projecting apparatus relatedto the third embodiment of the invention.

FIG. 8 is a flow chart showing the operation of shutter controller ofthe image projection converting apparatus as the image projectingapparatus related to the third embodiment of the invention.

FIG. 9 is an illustration showing a diagrammatic configuration of animage projection converting apparatus as an image projecting apparatusrelated to the fourth embodiment of the invention.

FIG. 10 is a block diagram showing a diagrammatic configuration of ashooter of the image projection converting apparatus shown in FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the invention will now be described in detail makingreference to the accompanying drawings.

FIG. 1 shows a diagrammatic configuration of the image projectingapparatus configured with the luminous source apparatus related to thefirst embodiment of the invention. An image projecting apparatusreferred to the embodiment is an image projection converting apparatushaving a shooter which is able to convert a projected image into anelectronic image signal (video signal), and is called telecinematographyapparatus.

The image projection converting apparatus 10 includes: a transportingmechanism 20 as to intermittently transport movie film 1, in which aseries of frame images is recorded at constant intervals; gate section30 consists of movable picture gate 31 and immovable picture gate 32,arranged below the movable picture gate 31 so as to put the movie film 1transported by the transporting mechanism 20 in between; the luminoussource apparatus 40 so as to project light onto the movie film 1 pausingat a prescribed position of the gate section 30. The movable picturegate 31 is able to move up and down when the movie film 1 is loaded.Openings(not shown in figures) are formed at each gate of the gatesection 30, so as to guide the light from the luminous source apparatus40 to a prescribed area of the movie film 1. The gate section 30 alsoincludes a film position detector(not shown in figures) so as to detectthe pausing position of the movie film 1.

The image projection converting apparatus 10 also includes: optical-axiscorrection/projection-lens section 50 having an optical-axis correctionmechanism(not shown in figures) performing optical-axis correctionaccording to the position of the movie film 1 detected from theabove-mentioned film position detector of the gate section 30, and aprojection lens(not shown in figures) performing condensation of theprojected light passed through the gate section 30; shooter 60constructed of such as a TV camera with an image pickup device such asCCD(charge-coupled device) and which performs electronization of therecorded information of the movie film 1, by shooting the projectedimage of the movie film 1, projected by the light from the luminoussource apparatus 40; and shutter mechanism 70 located between theluminous source apparatus 40 and the gate section 30, which interruptsor allows the light from the luminous source apparatus 40 to reach themovie film 1.

The transporting mechanism 20 is configured withcontinuously-transporting sprockets 21 a, 21 b which rotatecontinuously, and intermittently-transporting sprocket 22 which-rotatesintermittently. The continuously-transporting sprockets 21 a, 21 btransport the movie film 1 continuously, whileintermittently-transporting sprocket 22 transports the movie film 1intermittently in a prescribed interval near the gate section 30,according to film driving signal 74 from film transporting controller24.

The luminous source apparatus 40 includes: light-emission section 41configured with light-emission lamp 41 a such as xenon lamp andreflector 41 b; power supply 42 supplying a current to thelight-emission lamp 41 a; photosensor 43 detecting the light-emissionquantity of the light-emission lamp 41 a; light-quantity regulator 46outputting light-quantity regulating signal 46 to regulate thelight-emission quantity of the light-emission lamp 41 a so as to beconstant, based on light-quantity detecting signal 44 outputted from thephotosensor 43. The power supply 42 includes a control terminal(CTL), towhich the light-quantity regulating signal 45 from the light-quantityregulator 46 is inputted, and which controls a current supplied to thelight-emission lamp 41 a according to the light-quantity regulatingsignal 45. The luminous source apparatus 40 corresponds to one exampleof the luminous source apparatus related to the invention, thelight-emission lamp 41 a corresponds to one example of ‘the luminousbody’ of the invention, the photosensor 43 corresponds to one example of‘the means for detecting the light-quantity’ of the invention, and thelight-quantity regulator 45 corresponds to one example of ‘the means forregulating the light-quantity’ of the invention.

Shutter 73 included in shutter mechanism 70 consists of such as aliquid-crystal shutter, and performs opening/closing operation accordingto shutter opening/closing signal 72 from shutter controller 71. Theshutter controller 71 operates in synchronization with the filmtransporting controller 24.

According to telecinematography apparatus 10 having such configuration,the movie film 1 is transported intermittently by each frame bytransporting mechanism 20, and is projected by light from the luminoussource apparatus 40, when the film position detector of the gate section30 detects each frame image of movie film 1 pausing at prescribedposition of the gate section 30. To be more specific, the shutter 73 ofthe shutter mechanism 70 repeats opening and closing in synchronizationwith intermittently-transporting operation of the movie film 1,performed by intermittently-transporting sprocket 22, in accordance withfilm 1, driving signal 74 from the film transporting controller 24, andlight from the luminous source apparatus 40 is projected onto the moviefilm 1 passing through the opened shutter 73 of the shutter mechanism70, only when the movie film 1 is in pause state. Hereby, an imagerecorded in the movie film 1 is projected onto the shooter 60 throughthe optical-axis correction/projection-lens section 50. Besides, anexposure time of the movie film 1 is prescribed by the shutter mechanism70, in order to avoid shifts of image positions, which may occur whenthe intermittent transportation of the movie film 1 is set topickup-image timing.

FIG. 2 shows a diagrammatic configuration of the light-quantityregulator 46 shown in FIG. 1. As is shown in the figure, thelight-quantity regulator 46 includes: amplifier(AMP) 461 to which thelight-quantity detecting signal 44 from the photosensor 43 is inputted;low-pass filter(LPF) 462 connected to the output terminal of theamplifier 461 so as to cut a high-frequency component and only to let alow-frequency component pass through; differential amplifier 463outputting the light-quantity regulating signal 45 and supplying it tothe control terminal of the power supply 42. The minus terminal of thedifferential amplifier 463 is connected to the output terminal of thelow-pass filter 462, and the plus terminal is connected to the movableterminal of potentiometer 464, one end of which is connected to a powersupply voltage (+), and another end of which is grounded.

According to the light-quantity regulator 46 having such configuration,the inputted light-quantity detecting signal 44 is amplified in theamplifier, smoothed in the low-pass filter 462, and inputted to theminus terminal of the differential amplifier 463 as detectedlight-quantity voltage V(t). On the other hand, reference light-quantityvoltage V1 set up by the potentiometer 464 is inputted to the plusterminal of the differential amplifier 463. And the differentialamplifier 463 outputs the difference between the referencelight-quantity voltage V1 and the detected light-quantity voltage V(t),i.e. [V1−V(t)], as the light-quantity regulating signal 45. The V1 is aselected fixed voltage value, while the V(t) is a voltage value whichvaries accompanying with time (t).

Next, the operation and the effect of the image projection convertingapparatus 10 configured as mentioned above will now be described.

FIG. 3 shows the variation of the light-quantity detecting signal44(namely the light-quantity variation of the light-emission lamp 41 aof the luminous apparatus 40) outputted from the photosensor 43. Thevertical axis in the figure shows the detected light-quantity voltageV(t), while the horizontal axis shows time. As is shown in the figure,the light-quantity of the light-emission lamp 41 a varies enormously ina period of 0.5 to 5 seconds, and the variation quantity ΔV(t) reachesto about 2˜3%. Therefore, when an image is projected by projecting lightwhich includes such variation, onto the movie film 1, a video imageobtained through shooter 60 falls in including intensityvariation(flicker) resulting in the deterioration of image quality.According to the embodiment, as is described above, the light-emissionquantity of the light-emission lamp 41 a is detected, and a currentsupplied from the power supply 42 to the light-emission lamp 41 a isregulated according to the detected light-quantity so as to make thelight-emission quantity of the light-emission lamp 41 a constant. Thedetailed operation will be described in the following.

First, the whole operation of the image projection converting apparatus10 will be described. The intermittently-transporting sprocket 22 of thetransporting mechanism 20 intermittently transports the movie film 1 byrotating according to the film driving signal 74 from the filmtransporting controller 24. The shutter 73 of the shutter mechanism 70is maintained in closed state, while the movie film 1 is transported.When it is detected by the film position detector (not shown in figures)of gate section 30 that each image frame of the movie film 1 paused atthe prescribed position of the gate section 30, the shutter 73 of theshutter mechanism 70 is opened following the shutter opening/closingsignal 72 from the shutter controller 71, and light from thelight-emission lamp 41 a of the luminous source apparatus 40 isprojected onto the movie film 1 passing through the shutter 73 of theshutter mechanism 70. Hereby, the image recorded in the movie film 1 isprojected, and it reaches to the shooter 60 through optical-axiscorrection and light-gathering by the optical-axiscorrection/projection-lens section 50. The projected image received byan image pickup device not shown in figures, convertedphotoelectrically, and recorded in electronic-image recording mediumsuch as a video tape as an electronic image signal(video signal), afterpassing through various kinds of signal processing circuits. Besides,according to the embodiment, the opening period of the shutter 73 of theshutter mechanism 70 is a fixed period prescribed in advance.

Next, the characteristic operation of the image projection convertingapparatus 10 will be described. The light-emission lamp 41 a emits lightwith intensity according to the magnitude of the current supplied fromthe power supply 42. The photosensor 43 receives the light from thelight-emission lamp 41 a, outputs a voltage signal according to thelight-quantity as the light-quantity detecting signal 44, and inputs itto the light-quantity regulator 46. The light-quantity regulator 46amplifies the light-quantity detecting signal 44 at the amplifier 461,smoothes the amplified signal by rejecting a high frequency component atthe low-pass filter 462, and inputs the filtered signal to the minusterminal of the differential amplifier 463 as the detectedlight-quantity voltage V(t). The differential amplifier 463 takes thedifference between the reference light-quantity voltage V1 and thedetected light-quantity voltage V(t), i.e. [V1−V(t)], and outputs it asthe light-quantity regulating signal 45, supplying it to the controlterminal(CTL) of the power supply 42.

The power supply 42 varies the magnitude of the current provided to thelight-emission lamp 41 a in a manner to make the level of the inputtedlight-quantity regulating signal 45 approach zero. To be more specific,when the level of the light-quantity regulating signal 45 is positive,namely when V1>V(t), a current supplied to the light-emission lamp 41 ais increased by amount according to the absolute value of the difference[V1−V(t)], and when the light-quantity regulating signal 45 is negative,namely when V1<V(t), a current provided to the light-emission lamp 41 ais decreased by amount according to the absolute value of the difference[V1−V(t)]. The light-emission quantity of the light-emission lamp 41 aof the luminous source apparatus 40 is regulated to be constant, byperforming such control in a prescribed cycle(for example, a fewmilliseconds cycle). Such light without light-quantity variation likethis is projected onto the movie film 1 performing image projection,resulting in obtaining a video signal without flicker by the shooter 60.

According to the embodiment of the image projection converting apparatus10, the photosensor 43 detecting the light-emission quantity of thelight-emission lamp 41 a is provided, and the current provided from thepower supply 42 to the light-emission lamp 41 a according to thelight-quantity detecting signal 44 from the photosensor 43 is regulatedso as to make the light-emission quantity of the light-emission lamp 41a constant. Therefore, the image obtained by the shooter 60 becomes animage with good quality with a little flicker(intensity variation). Andalso makes it possible to compensate the light-quantity reduction of thelight-emission lamp 41 a caused through secular changes.

Next, the second embodiment of the invention will now be described.

FIG. 4 shows a diagrammatic configuration of an image projectionconverting apparatus as an image projecting apparatus related to thesecond embodiment of the invention. In the figure, the same marks as theone used in the above-mentioned first embodiment(FIG.1) represent thesame configuration elements, and explanation will be omitted suitably.

According to image projection converting apparatus 10 a of theembodiment, the light-quantity detecting signal 44 from the photosensor43 is inputted to shutter controller 71 a. The light-quantity regulator46 is not provided, and a control terminal is not included in powersupply 42 a. As will be described, the shutter controller 71 a of theembodiment performs control as follows. The shutter controller 71 aopens the shutter 73 of the shutter mechanism 70 under control ofshutter opening/closing signal 72, according to the film driving signal74 from the film transporting controller 24. At the same time, theshutter controller 71 a begins to integrate the light-quantity detectingsignal 44 from the photosensor 43. And the shutter controller 71 acloses the shutter 73 of the shutter mechanism 70 when the obtainedintegral L(t) of light-quantity has reached to a prescribed referenceintegral L1. Other configurations are as same. as the above-mentionedfirst embodiment. The shutter mechanism 70 corresponds to one example of‘the means for opening/closing light-path’, and the shutter controller71 a corresponds to one example of the ‘means for controllingopening/closing light-path’.

Next, the operation and the effect of the image projection convertingapparatus 10 a having such configuration will now be described makingreference to FIG. 5 and FIG. 6. FIG. 5 shows the operation timing of theimage projection converting apparatus 10 a. The film driving signal 74is shown as (a) in the figure, and “H” level zone indicates the pausingstate of the movie film 1, while “L” level zone indicates thetransporting state. The shutter opening/closing signal 72 is shown as(b) in the same figure, and “H” level zone indicates the closing stateof the shutter 73 of the shutter mechanism 70, while “L” level zoneindicates the opening state. The variation of the light-quantitydetecting signal 44 is shown as (c) in the same figure, while (d) in thesame figure shows the accumulated electrical-charge quantity of thepickup device(CCD is supposed here) at the shooter 60 not shown infigures. And FIG. 6 shows the operation of the shutter controller 71 a.

When the movie film 1 pauses by changing the film driving signal 74 from“L” level to “H” level (FIG. 6 step S101; Y), the shutter controller 71a resets a timer not shown in figures, and begins time-count operation(step S 102). When the time-count value reaches to a fixed value t1shown in FIG. 5(b)(step S103; Y), the shutter controller 71 a opens theshutter 73 of the shutter mechanism 70 by changing the shutteropening/closing signal 72 from “H” level to “L” level. At the same time,the controller 71 a begins the integration of the light-quantitydetecting signal 44, and computes the integral L(t) of light-quantityshown as the diagonally shaded area in (c) of FIG. 5(step S104). Theintegral L(t) of light-quantity corresponds to one example of the‘accumulated light-quantity’ of the invention.

When the shutter 73 of the shutter mechanism 70 is opened, light fromthe light-emission lamp 41 a is projected onto the image frame of themovie film 1, and the image is projected onto the CCD of the shooter 60.Hereby, the accumulation of charge corresponding to the projected imagebegins in the CCD of the shooter 60 (FIG. 5(d)).

When the integral L(t) of light-quantity obtained through theintegration of the light-quantity detecting signal 44 reaches to thereference integral L1(step S 105; Y), the shutter controller 71 achanges the shutter opening/closing signal 72 to “H” level, closing theshutter 73 of the shutter mechanism 70(step S 106). The shutter openingperiod differs depending on the level of the light-quantity detectingsignal 44. In other words, when the level of the light-quantitydetecting signal 44 is high, the shutter opening period t2 becomesshorter, while the level of the light-quantity detecting signal 44 islow, the shutter opening period t2′ becomes longer.

When the shutter 73 of the shutter mechanism 70 is closed, the lightfrom the light-emission lamp 41 a is interrupted, and the chargeaccumulation in the CCD of the shooter 60 finishes. The chargeaccumulated in the CCD of the shooter 60 is read at the readout-timingin the following (FIG. 5(d)), and outputted as a video signal afterpassing several kinds of signal processing.

As described above, according to the image projection convertingapparatus 10 a of the embodiment, the integral L(t) light-quantity iscontrolled so as to be a constant value(reference integral L1) at alltimes through the opening/closing operation of the shutter 73 of theshutter mechanism 70. Therefore, the shutter opening period changesaccording to the light-emission quantity of the light-emission lamp 41a. Hereby, the accumulated exposure quantity(corresponds to one exampleof the ‘accumulated projected light-quantity’ of the invention) of themovie film 1 is regulated to be constant, regardless of the magnitude ofthe light-quantity of the light-emission lamp 41 a. As a result, thecharge-quantity accumulated in the CCD of the shooter 60 will not beeffected by the light-quantity variation of the light-emission lamp 41a, and the accumulated charge-quantity of CCD becomes nearlyconstant(e1=e2 in FIG. 5(d)) at each frame, if the transmissivity of themovie film 1 is constant. Therefore, the video signal obtained throughthe shooter 60 hardly includes intensity variation(flicker) caused bylight-quantity variation of the light-emission lamp 41 a. Furthermore,the intensity level of the obtained video signal is maintained constant,even the light-quantity of the light-emission lamp 41 a reduces throughsecular changes.

The third embodiment of the invention will now be described.

Image projection converting apparatus 10 b as an image projectingapparatus of the embodiment is provided with shutter controller 71 b inplace of shutter controller 71 a in FIG.4 concerned with theabove-mentioned second embodiment. As will be described, the shuttercontroller 71 b previously integrates the light-quantity detectingsignal 44 from the photosensor 43 before opening the shutter 73 of theshutter mechanism 70, and changes the opening period of the shutter 73of the shutter mechanism 70 according to the magnitude of the obtainedintegral L(t) of light-quantity. Other configurations are the same withFIG.4.

Next, the operation and the effect of the image projection convertingapparatus 10 b having such configuration, will now be described makingreference to FIG. 7 and FIG. 8. FIG. 7 shows the operation timing of theimage projection converting apparatus 10 b, and (a)˜(d) in the figurecorrespond to (a)˜(d) in FIG. 5. And FIG.8 shows the operation of theshutter controller 71 b.

When the movie film 1 starts running at the point of changing of thefilm driving signal 74 from “H” level to “L” level(FIG. 8 step S201; Y),the shutter controller 71 b resets a timer not shown in figures, andbegins time-count operation (step S202). The shutter controller 71 bbegins the integration of the light-quantity detecting signal 44(stepS204), when the time-count value reaches to a fixed value t4 shown inFIG. 7(b) (step S203; Y). At the same time, the shutter controller 71 bbegins the time-count operation after resetting a timer not shown infigures(step S205).

The shutter controller 71 b finishes the integration of thelight-quantity detecting signal 44 to obtain the integral L(t) oflight-quantity, when the time-count value reaches to a fixed value t5shown in FIG. 7(b) (step S206; Y). The shutter controller 71 b obtainsshutter opening period t6 based on the integral L(t) of light-quantity,and opens the shutter 73 of the shutter mechanism 70 by changing theshutter opening/closing signal 72 from “H” level to “L” level(stepS207). At the same time, the shutter controller 71 b begins time-countoperation after resetting a timer not shown in figures(step S208). Theshutter opening period t6 corresponds to one example of the ‘light-pathopening period’ of the invention, and the integral L(t) oflight-quantity to one example of the ‘accumulated light-quantity’ of theinvention.

The shutter opening period t6 is obtained by expression (2) below, usingcoefficient α(t) given by expression (1) below.α(t)=1+(L 2 −L(t))/L 2  (1)t 6=τ×α(t)  (2)

-   -   L2 represents reference accumulated light-quantity, and τ        represents reference shutter opening period corresponds to the        reference accumulated light-quantity L2.

As is obvious from expression (1) and (2), the shutter opening period t6changes according to the magnitude of the obtained integral L(t) oflight-quantity. To be more specific, the shutter opening period t6 isshorter than τ when L2<L(t), and shutter opening period t6′ is longerthan τ when L2>L(t) as shown in FIG. 7(c).

When the shutter 73 of the shutter mechanism 70 is opened, light fromthe light-emission lamp 41 a is projected onto the image frame of themovie film 1, projecting the image onto the CCD of the shooter 60.Hereby, the accumulation of the charge corresponding to the projectedimage starts in the CCD of the shooter 60 as shown in FIG. 7(d).

The shutter controller 71 b closes the shutter 73 of the shuttermechanism 70 by changing the shutter opening/closing signal 72 to “H”level(step S210), when the time-count value of the timer reaches to thevalue t6, obtained at the step S207(step S209; Y).

When the shutter 73 of the shutter mechanism 70 is closed, light fromthe light-emission lamp 41 a is interrupted, and the charge accumulationin the CCD of the shooter 60 finishes. The charge accumulated in the CCDof the shooter 60 is read at the readout-timing in the following (FIG.7(d)), and recorded in such as video tape as a video signal afterseveral kinds of signal processing.

In this way, according to the image projection converting apparatus 10b, the light-quantity detecting signal 44 is previously integrated for agiven period obtaining the integral L(t) of light-quantity; beforeopening the shutter 73 of the shutter mechanism 70, and the openingperiod of the shutter 73 (i.e. light-path closing timing) is changedaccording to the magnitude of the integral L(t) of light-quantity.Hereby, the accumulated exposure quantity of the movie film 1 isregulated to be constant, regardless of the magnitude of thelight-emission quantity of the light-emission lamp 41 a. As a result,the charge-quantity accumulated in the CCD of the shooter 60 will not beeffected by the light-quantity variation of the light-emission lamp 41a, and the accumulated charge-quantity becomes nearly constant(e3=e4 inFIG. 7(d)) if the transmissivity of the movie film 1 is constant.Therefore, the video signal obtained through the shooter 60 hardlyincludes intensity variation(flicker) caused by light-quantity variationof the light-emission lamp 41 a. Furthermore, the intensity level of theobtained video signal is maintained constant, even the light-quantity ofthe light-emission lamp 41 a reduces through secular changes.

Next, the fourth embodiment of the invention will now be described.

FIG. 9 shows a diagrammatic configuration of an image projectionconverting apparatus as an image projecting apparatus related to thefourth embodiment of the invention. In the figure, the same marks as theone used in the above-mentioned first and second embodiments (FIG. 1,FIG. 4) represent the same configuration elements, and explanations willbe omitted suitably.

According to image projection converting. apparatus 10 c of theembodiment, shooter 60 a is supplied with the light-quantity detectingsignal 44 from the photosensor 43. The light-quantity regulator 46 inFIG. 1 is not provided, and a control terminal is not included in thepower supply 42 a. The shutter controller 71 each time performsframe-by-frame shutter control so that the opening period becomeconstant, as is the same case with the above-mentioned first embodiment.The shooter 60 a is provided with a gain control signal generator aswill be seen, in the image projection converting apparatus 10 c .

FIG. 10 shows the configuration of main sections of the shooter 60 a. Asis shown in the figure, the shooter 60 a includes: image-pickup lens 61for forming the image of the movie film 1 projected through theoptical-axis correction/projection-lens section 50(FIG. 9); image-pickupdevice 62 consists of CCD, placed at the focus position of theimage-pickup lens 61 so as to convert light-quantity of the incidentlight into a charge-signal and to accumulate it; voltage controlamplifier(VCA)63 amplifying the pixel-signal read from the image-pickupdevice 62; and the gain control signal generator 65. In the voltagecontrol amplifier 63, gain is variably controlled by gain control signal66, inputted to regulator 63 a from the gain control signal generator65. The voltage control amplifier 63 and the gain control signalgenerator 65 corresponds to one example of the ‘means for regulatingintensity lever’ of the invention.

The gain control signal generator 66 includes: amplifier (AMP) 651 towhich the light-quantity detecting signal 44 from the photosensor 43 isinputted; low-pass filter(LPF) 652 connected to the output terminal ofthe amplifier 651 so as to cut a high frequency component and only let alow frequency component pass through; differential amplifier 653, theminus terminal of which is connected to the output terminal of thelow-pass filter 652, while the plus terminal of which is connected tothe movable terminal of the potentiometer 654, connected between thepower supply voltage(+) and the ground; and computing section 655connected to the output terminal of the differential amplifier 653.

The light-quantity detecting signal 44 inputted to the gain controlsignal generator 65 is amplified in the amplifier 651, smoothed in thelow-pass filter 652 and inputted to the minus terminal of thedifferential amplifier 653 as detected light-quantity voltage V(t). Onthe other hand, reference light-quantity voltage V2 set up by thepotentiometer 654 is inputted to the plus terminal of the differentialamplifier 653. And the differential amplifier 653 outputs the differencebetween the reference light-quantity voltage V2 and the detectedlight-quantity voltage V(t), namely [V2−V(t)]. The V2 here is a selectedfixed voltage value. For example, the computing section 655 computescoefficient β(t) shown in the next expression (3) based on thedifference signal[V2−V(t)] outputted from the differential amplifier653, and supplies the result to the regulator 63 a of the voltagecontrol amplifier 63 as the gain control signal 66.β(t)=1+(V 2−V(t))V 2  (3)Other configurations are the same with the above-mentioned firstembodiment.

Next, the operation and the effect of the image projection convertingapparatus 10 c having such configuration will now be described. Thelight-quantity detecting signal 44 outputted from the photosensor 43 isinputted to the gain control signal generator 65 of the shooter 60 a.The gain control signal generator 65 amplifies the signal in theamplifier 651, smoothes the inputted light-quantity detecting signal 44by cutting a high frequency component in the low-pass filter 652, andinputs the result to the minus terminal of the differential amplifier653 as a detected light-quantity voltage V(t). The differentialamplifier 653 takes the difference between the reference light-quantityvoltage V2 and the detected light-quantity voltage V(t), namely[V2−V(t)], and supplies it to the computing section 655. The computingsection 655 computes β(t) by the expression (3), and supplies the resultto the regulator 63 a of the voltage control amplifier 63 as the gaincontrol signal 66. The regulator 63 a regulates the gain of the voltagecontrol amplifier 63 according to the value of the gain control signal66. become more specific, when V2>V(t), the gain of the voltage controlamplifier 63 is regulated so as to increase, as the value β(t) of thegain control signal 66 becomes larger than 1, while when V2<V(t), thegain of the voltage control amplifier 63 is controlled so as todecrease, as the value β(t) becomes smaller than 1.

By performing such control in a prescribed cycle(for example, a fewmilliseconds cycle), the intensity level of the video signal outputtedfrom the voltage control amplifier 63 of the shooter 60 is regulated soas to. compensate the light-quantity variation of the light-emissionlamp 41 a. Hereby, an image obtained through the shooter 60 a is noteffected by the light-quantity variation of the light-emission lamp 41a, and hardly includes intensity variation.

According to the embodiment of the image projection converting apparatus10 c , the photosensor 43 detecting the light-emission quantity of thelight-emission lamp 41 a is provided, regulating the level of the videosignal generated in the shooter 60 a according to the light-quantitydetecting signal 44 from the photosensor 43. Hereby the image obtainedthrough the shooter 60 becomes an image with good quality with a littleintensity variation, in spite of the intensity variation of theprojected image caused by the light-quantity variation of thelight-emission lamp 41 a. Furthermore, the intensity level of theobtained video signal is maintained constant, regardless of thereduction of the light-quantity of the light-emission lamp 41 a causedthrough secular changes.

Though a couple of embodiments were given to explain the invention sofar, the invention may be embodied in various other ways not being.limited to these embodiments. For example, although an image projectionconverting apparatus. called telecinematography apparatus, performingelectronization of a projected image by a pickup device is illustratedas an example in the above-mentioned embodiments, the luminous sourceapparatus of the invention is also available for example in a normalprojector, performing image projection onto a screen, or in aliquid-crystal projector.

According to the image projecting apparatus of the invention, asdescribed so far, the light-quantity emitted from the luminous body isdetected and as the light-quantity emitted from the luminous body isregulated based on the result of the detection so as to make theprojected light-quantity onto the recording medium constant. As aresult, it becomes possible to suppress the harmful intensity variationof the image projected by the projected light, resulting in obtaining aprojected image with stable image quality. Furthermore, the secularchanges of the light-quantity of the luminous body will also be avoided.

According to another image projecting apparatus of the invention, thelight-quantity emitted from the luminous body is detected, and as theaccumulated projected light-quantity onto the recording medium isregulated to be constant by performing closing or opening the light-pathfrom the luminous body to the recording medium. As a result, it becomespossible to avoid the intensity variation of the projected image causedby the light-quantity variation of the luminous body. Furthermore, theintensity level of the projected image will be maintained in a propercondition, regardless of the secular changes of the light-quantity ofthe luminous body.

According to the image projection converting apparatus of the invention,the light-quantity emitted from the luminous body is detected, and theintensity level of the image signal, obtained by the means forpicking-up image which picks up the image projected by the light fromthe luminous body, is regulated based on the result of the detection. Asa result, it becomes possible to avoid the intensity variation of thepicked up image signal caused by the light-quantity variation of theluminous body. Furthermore, the intensity level of the picked-up imagewill be maintained in a proper condition regardless of the secularchanges of the light-quantity of the luminous body.

Obviously any modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practice otherwise than as specifically described.

1. An image projecting apparatus, performing image projection byprojecting light onto a recording medium in which an image is recorded,comprising: a luminous body emitting light to be projected onto therecording medium; means for detecting the light-quantity emitted formthe luminous body; means for directly regulating the light-quantityemitted from the luminous body based on the result of detection by themeans for detecting the light-quantity, so as to make the light-quantityemitted by the luminous body and therefore the light-quality projectedonto the recording medium constant; and means for converting an imageprojected from the recording medium in accordance with thelight-quantity projected onto the recording medium into a digital image,and for recording the digital image in digital recording means.
 2. Animage projecting apparatus according to claim 1 wherein the recordingmedium, in which an image is recorded, is a movie film.
 3. An imageprojecting apparatus according to claim 1 wherein the recording medium,in which an image is recorded, is a group of liquid-crystal displaydevices.
 4. An image projecting apparatus, performing image projectionby projecting light onto a recording medium in which an image isrecorded, comprising: a luminous body emitting light to be projectedonto the recording medium; means for directly detecting thelight-quantity emitted from the luminous body; means for closing andopening the light-path from the luminous body to the recording medium;means for controlling the opening/closing operation of the means foropening/closing light-path based on the result of the detection by themeans for detecting the light-quantity in order to make the accumulatedlight-quantity projected onto the recording medium constant; and meansfor converting an image projected from the recording medium inaccordance with the light-quantity projected onto the recording mediuminto a digital image, and for recording the digital image in digitalrecording means.
 5. An image projecting apparatus according to claim 4wherein the means for controlling opening/closing light-path begins theaccumulation of the light-quantity detected by the means for detectingthe light-quantity at the point of making the means for opening/closinglight-path in opened state, and makes the means for opening/closinglight-path in closed state at the point of the accumulatedlight-quantity has reached to prescribed value.
 6. An image projectingapparatus according to claim 4 wherein the means for controllingopening/closing light-path accumulates the light-quantity detected bythe means for detecting the light-quantity for a given period beforemaking the means for opening/closing light-path in opened state, whileobtaining the opening period of light-path of the means foropening/closing light-path based on the accumulated light-quantity, andmakes the means for opening/closing light-path in opened state for theobtained opening period of light-path.
 7. An image projecting apparatusaccording to claim 4 wherein the means for opening/closing light-pathcomprises a liquid-crystal shutter.
 8. An image projecting apparatusaccording to claim 5 wherein the means for opening/closing light-pathcomprises a liquid-crystal shutter.
 9. An image projecting apparatusaccording to claim 6 wherein the means for opening/closing light-pathcomprises a liquid-crystal shutter.
 10. An image projecting apparatusaccording to claim 4 wherein the recording medium, in which an image isrecorded, is a movie film.
 11. An image projecting apparatus accordingto claim 5 wherein the recording medium, in which an image is recorded,is a movie film.
 12. An image projecting apparatus according to claim 6wherein the recording medium, in which an image is recorded, is a moviefilm.
 13. An image projecting apparatus according to claim 4 wherein therecording medium, in which an image is recorded, is a group ofliquid-crystal display devices.
 14. An image projecting apparatusaccording to claim 5 wherein the recording medium, in which an image isrecorded, is a group of liquid-crystal display devices.
 15. An imageprojecting apparatus according to claim 6 wherein the recording medium,in which an image is recorded, is a group of liquid-crystal displaydevices.
 16. An image projecting apparatus according to claim 4 wherein:the recording medium, in which an image is recorded, is a movie filmtransported intermittently in one direction; the means foropening/closing light-path is a liquid-crystal shutter; and the meansfor controlling opening/closing light-path controls the openingoperation of the means for opening/closing light-path in synchronizationwith the intermittent transportation of a movie film, while controllingthe closing operation of the means for opening/closing light-path basedon the result of the detection by the means for detecting the light-,quantity in order to make the accumulated light-quantity projected ontothe recording medium constant.
 17. An image projection convertingapparatus, performing image projection by projecting light onto arecording medium in which an image is recorded, comprising: a luminousbody emitting light to be projected onto the recording medium; means fordirectly detecting the light-quantity emitted from the luminous body;means for picking up an image projected from the recording medium inaccordance with the light-quantity projected onto the recording mediummeans for regulating an intensity level of the picked up image based onthe result of the detection of the means for detecting thelight-quantity by directly regulating the light-quantity emitted fromthe luminous body; and whereby said means for picking up an imageconverts the picked up image into a digital image and records thedigital image in digital recording means.
 18. An image projectionconverting apparatus according to claim 17 wherein the recording medium,in which an image is recorded, is a movie film transportedintermittently in one direction, comprising: means for closing andopening the light-path from the luminous body to the recording medium;and means for controlling the opening/closing operation of the means foropening/closing light-path in synchronization with the intermittenttransportation of the movie film.